In recent times much work has been done concerning the development of solar energy heating systems for homes and other like building structures. In such typical systems solar energy is gathered via a solar energy collector which converts the solar energy into heat energy. The heat energy is transferred from the collector to a circulating fluid with the circulated fluid giving up its heat to the interior of the home. While such systems have met with a limited degree of success, one of the problems has been utilization of solar energy collected during times of the year when there is no heating need on the home such as for example certain times of the spring, fall and especially during the summer. The problem is especially difficult during the spring and fall when often times during the day the home has no heating requirement but since the temperature cools rapidly in the evening, there is a heating need during this period of time when no sun energy for conversion into heat energy is available. This disadvantage of solar heating systems has been to a limited degree overcome by utilization of thermal storage systems. In such systems heat is transferred from a warmed collector plate of the solar collector to a heat transfer medium circulated therewithin. The warmed heat transfer medium is pumped away from the collector and to a remotely located thermal storage system. Typically, the thermal storage system is comprised of a storage vessel filled with water or a highly efficient heat transfer material such as Glauber's salt or the like. The warmed circulating heat transfer medium is passed through the storage unit and gives up its heat to the thermal storage system. Thereafter, when the air space of the home or other building structure is at a lower temperature than the thermal storage unit, heat is transferred from the remote position of the thermal storage unit to the interior of the home. In this manner collection and storage of solar energy in the form of heat energy has been utilized in the past. However, such structures utilizing remotely located thermal storage tanks, vessels or the like have certain inherent disadvantages. First, with remotely located storage units there is inherently always some heat loss which of course decreases efficiency of the overall system. Secondly, such remotely located thermal storage systems can only maintain and store heat for a certain defined limited period of time and if the heat is not used during that period of time, it eventually dissipates without any significant advantage to the user. This is especially important when long periods, such as for example two to three weeks, of cloudy weather occurs. Thirdly, the use of remotely located thermal storage systems involves the building of special apparatus, coupled with the necessary duct work, which would not ordinarily be present in the home structure thereby increasing substantially the cost. Fourthly, some of the special equipment needed for the prior art thermal storage systems is unique to solar energy usage and cannot be utilized for any other use within the home heating and cooling system. Fifthly, such prior art thermal storage systems result in loss of valuable floor space coupled with a high cost for storage of the heat. Sixthly, with prior art systems when no heating or cooling is required, the collected solar energy is essentially wasted since it is dissipated to the exterior of the home. This condition unfortunately occurs often during the spring and fall seasons which is exactly when collectors operate most efficiently because of their orientation with respect to the angle of the sun. Thus during the period of the year at which the solar heating system has its greatest potential for most efficient operation, much of the heat gathered is not utilized.
The solar power system of this invention, described in detail below, eliminates each and every one of the above-mentioned disadvantages. First, since no physical heat storage occurs within the solar power system of this invention, it eliminates the high cost of storage and loss of valuable floor space. Secondly, when neither heating or cooling is required, the system will switch to operating electrical home appliance needs and feeding excess generated electricity to a utility power grid for a credit and immediate redistribution by the utility. Thirdly, since the system operates year around, smaller collector areas are needed to achieve the same equivalent energy production as in a thermal storage unit. This results in lower material and installation costs. Fourthly, the solar power system of this invention takes advantage of the highly efficient spring and fall seasons to collect and utilize to the fullest extent solar power generated during those seasons.
Other advantages of the solar power system of this invention are many. For example, compared to most solar thermal storage systems, the solar power system of this invention exhibits an economy of equipment and simplicity of operation. Fewer pieces of equipment utilized results in conservation of energy expended for materials, manufacturing, and installation costs. Also, the solar power system of this invention, and more specifically the direct boil solar collector, hereinafter described, is more efficient than typical water and air collector systems in several ways which will be discussed hereinafter. In the collector of this invention, the solar heat is transferred directly to a refrigerant and immediately used by transfer to kinetic energy via a Rankine cycle engine thereby avoiding the immediate step of transferring heat to storage equipment and then to appropriate power equipment.
Another unique advantage of the solar power system of this invention is that excess solar power not utilized or needed for immediate heating or cooling demand within the home is converted to electrical energy and returned to a utility power grid for a credit. The utility can thereafter immediately redistribute the generated electrical current to other users. Thus the storage is in effect a mere credit storage on paper, balancing the electrical consumption by a home owner against the electrical generation produced by the home owner in his solar power system.
The method of accomplishing these advantages and objects of the invention, as well as others, will become apparent from the detailed description of the invention provided hereinafter.